DISPERSAL OF EPIPHYAS-POSTVITTANA (WALKER) AND PLANOTORTRIX OCTO DUGDALE (LEPIDOPTERA, TORTRICIDAE) AT A CANTERBURY, NEW-ZEALAND ORCHARD

Mated pairs of Epiphyas postvittana and Planotortrix octo were marked and released at a point source in a young, 40 ha orchard. Port wine ba it traps and pheromone traps along eight radiating transects were chec ked daily. In 1988, recapture of E. postvittana was 0.24% of females i n bait traps, 0.23% of males in bait traps, with 3.4% of males in pher omone traps. In 1990, recapture of both male and female E. postvittana was more successful (12.2% of females in bait traps, 4.4% of males in bait traps, and 12.4% of males in pheromone traps). No marked males a nd only one marked female P. octo were recaptured in bait traps, altho ugh 5.1% of males were recaptured in pheromone traps. The maximum disp ersal distance recorded for E. postvittana males was 600 m, but 80% of released males were recaptured within 100 m. For female E. postvittan a, the maximum distance recorded was 275 m, with 99% dispersing 100 m or less. Male P. octo exhibited similar dispersal capability to male E . postvittana, with a maximum of 400 m recorded. Wild male and female E. postvittana were very abundant, with 4629 males caught in pheromone traps and 615 males caught in bait traps, with 948 females caught in bait traps.